The present invention is related to wireless telecommunication systems. More particularly, and not by way of limitation, the present invention is directed to a system and method for providing enhanced user privacy when utilizing Location Services (LCS) in mobile telephone networks.
The present invention, and the current state of the art, are described herein in terms of the General Packet Radio Service (GPRS). Terminology and abbreviations within the technical field of GPRS, well known for persons skilled in the art, are utilized in this application. The Third Generation Partnership Project (3GPP) Technical Specification (TS) 23.271 is hereby incorporated by reference herein, and provides a detailed description of LCS in GPRS networks.
Higher data speeds in wireless telecommunication systems enable operators to offer new types of services. One such service type is LCS, which are services providing mobile telephone users with information about the location of objects or persons. This information may be presented on the user terminal, for example, on a digital map, or as an audio or text message indicating a position, address, or place name.
Further, LCS services may be considered as a network-provided enabling technology consisting of standardized service capabilities, which enable the provision of location-based applications. The main network component for providing LCS services is the GMLC (Gateway Mobile Location Center), to which all location requests are transmitted, and which, in return, provides the requested location from the mobile network. The application(s) may be service-provider specific, for example tracking of persons or vehicles. However, the description of the numerous and varied possible location applications that are enabled by this technology are outside the scope of the present application.
There is a need to enhance the privacy mechanisms provided for LCS services to support the increasing number of LCS clients and the varying privacy requirements for location services. It is also desirable for the subscriber to have the capability to set or change the location-related privacy parameters in the subscriber's home network. Current LCS specifications in 3GPP are limited in regards to user privacy, and in particular there is a need to enhance the privacy mechanisms, for example, for roaming subscribers. In the current specifications, only limited screening for privacy is possible. The screening is based on the “LCS client ID” parameter of the Provide Subscribe Location message utilized in the Mobile Application Part (MAP) protocol. The Provide Subscribe Location message is utilized by the GMLC to request the subscriber's location from the Serving GPRS Support Node (SGSN) or Mobile Switching Center (MSC). The SGSN or MSC maps the received LCS client ID parameter to the subscriber's recorded privacy parameters (e.g., list of allowed LCS clients) to screen out any unwelcome location requests. In practice, there is a need to have a more detailed service-type screening, for example, to differentiate between a “Where am I” type of service and games or entertainment services.
Additionally, it is difficult for a subscriber to use local location-based services when roaming. The subscriber does not have proper means to add local LCS clients to the allowed LCS client list in the home environment Home Location Register (HLR). Furthermore, the privacy parameters are defined with a quite narrow scope in the HLR, which may make it difficult for the subscriber to set additional and varying privacy parameters for each LCS client. According to the current specifications, the subscriber cannot receive any information regarding who originally asked for the location of the subscriber. It would be desirable for the subscriber to be notified of the identity of the requestor. It would also be desirable for the location information to be given only to those requestors who are entitled to have it. In order to protect the UE (User Equipment) against unwelcome location requests, LCS services should support a screening function that denies the unwelcome accesses to the UE. The current LCS specification, however, only supports the screening mechanism using the external identity of the LCS client. Thus, there is a need to enhance the screening mechanism.
The most recent 3GPP Technical Report (TR) addressing this subject is 3GPP TR 23.871, version 1.1.0, which is hereby incorporated by reference herein. TR 23.871 identifies and describes the service requirements for user privacy in LCS services, and the corresponding functional requirements have been created, and some alternatives for possible solutions are introduced. The first part of TR 23.871 describes the corresponding stage 1 type of service requirements, and may be moved to the LCS Stage 1 specification TS 22.071. Stage 1 includes a set of requirements that shall be supported for the provision of user privacy in location services, seen primarily from the subscriber's and service providers' points of view. The TR describes some possible enhancements to the privacy mechanisms provided for LCS services to support the increasing number of LCS clients and the varying privacy requirements for location services. The second part of TR 23.871 describes the Stage 2 type of functional requirements for enhancing user privacy in location services, and may be moved to the LCS Stage 2 specification TS 23.271.
TR 23.871 presents four different proposed solutions on how to provide enhanced privacy checking.                1) Enhanced privacy handled in a new network node that is connected to the GMLC with a new interface.        2) Enhanced privacy handled in a new network node that is connected to the SGSN/MSC with a new interface.        3) Enhanced privacy handled in a GMLC located in the subscriber's home Public Land Mobile Network (HPLMN) that is connected to a GMLC in a Visited PLMN (VPLMN).        4) Enhanced privacy handled in a new network node that is connected to the subscribers Home Subscriber Server (HSS) with a new interface.        
A major problem with the existing alternative solutions proposed in TR 23.871 is that they all require changes in the existing architecture, i.e., new interfaces and/or new network nodes. Changing the existing architecture would have high costs for both manufacturers and operators who already use the current agreed architecture. Moreover, several problems affecting new architectures have been identified, as reported in the TR.